Microbiology for usmle - quizlet Flashcards
N. meningitis
Gram- coccus, ferments maltose
S. Aureus
Gram+ coccus, catalase+, coagulase+
S. Pyogenes, S. Agalactiae
Gram+ coccus, catalase-, B-hemolysis
S. epidermitis, S. saprophyticus
Gram+ coccus, catalase+, coagulase-
S. Pneumoniae, S. Viridans
Gram+ coccus, catalase-, a hemolysis
Enterococcus
Gram+ coccus, catalase-, y hemolysis
S. Pneumoniae
Gram+ coccus, catalase-, bile soluble
S. Pneumoniae
Gram+ coccus, quellung+
Listeria
Gram+ rod, has endotoxin
Clostridium, Bacteroides, Actinomyces
Aminoglycosides are ineffective
K. Pneumoniae, Salmonella, HiB
Gram- rod, quellung+
C. diptheriae
AB toxin inactivates EF-2
ETEC
AB toxin (1) activates adenylate cyclase (=> cAMP); AB toxin (2) stimulates guanylate cyclase
B. pertussis
AB toxin inhibits G(i) protein => increased cAMP
C. diptheriae
Has an AB toxin that is similar to Pseudomonas exotoxin A in effect
B. anthracis
Has edema factor (=> cAMP)
Streptolysin O
Antibody used to dx RF
C. botulinum
Blocks Ach release
C. tetani
Blocks GABA and glycine release
S. pneumoniae, HiB, N. meningitis
Has bacterial competence
Listeria
Gram + rod, B hemolysis
S. Aureus, other catalase producing organisms
Affects those with chronic granulomatous disease
S. pneumoniae
Rusty sputum. Causes sepsis in those with sickle cell anemia, and asplenic patients
S. pneumoniae, HiB, N. meningitis
Has IgA protease
S. pyogenes
Avoids phagocytosis using M protein
S. bovis
Causes bacteremia and subacute endocarditis in colon cancer patients
Clostridium, B. anthracis
Gram+ rod, spore forming
B. anthracis
Has a polypeptide capsule with D-glutamate
Actinomyces israelii
Forms sulfur granules in sinus tracts
M. leprae
Gram+ bacillus, grows in live cells only.
M. leprae (lepromatous form)
Loss of eyebrows, nasal collapse, lumpy earlobe
K. pneumoniae, E. coli
Gram- rod, lactose fermenter
Pseudomonas
Gram- rod, non-lactose fermenting, oxidase+
Shigella, Salmonella, Proteus
Gram- rod, non-lactose fermenting, oxidase-
Gram- rods
Resistant to penicillin G and vancomycin, but may be sensitive to derivative (ie ampicillin)
H. influenza
Requires NAD and hematin for growth
Legionella
Gram- rod, requires silver stain for visualization
Legionella: erythromycin
Gram- rod, needs iron and cysteine for growth. Treat with?
Pseudomonas: aminoglycoside + extended spectrum PCN
Causes malignant otitis externa in diabetics. Treat with?
Pseudomonas
Produces exotoxin A => inactivates EF-2
Enterobacteria. All are lactose fermenters and oxidase negative
Have O, K, and H antigens
EHEC
Has a Shiga-like toxin. Causes necrosis and inflammation. Does not invade mucosa.
EPEC
Gram- rod. Causes diarrhea by flattening villi - no toxin. Associated with clusters.
K. Pneumoniae
Causes aspiration pneumoniae, lung abscesses. Infects alcoholics and diabetics. Also causes nosocomial UTI
EIEC
Has a Shiga-like toxin, but mucosal invasion is what causes necrosis/inflammation.
Typhoid fever, caused by Salmonella typhi
Fever, diarrhea, HA, rose spots on abdomen
Salmonella
Non-lactose fermenting gram-rod; has flagella and produces H2S
Salmonella
Remains in gallbladder chronically
Yersinia enterocolitica
Mimics Crohn’s and appendicitis. Major source: pigs
H. pylori
Gram- rod, urease+. Risk factor for peptic ulcer, gastric adenocarcinoma, and lymphoma
Spirochetes
Visualized with dark field microscopy
Borrelia burgorferi: Ixodes tick: doxycycline, ceftriaxone
Causes erythema migrans, bilateral Bell’s palsy, AV block, and arthritis. Source? Treat with?
Whipple’s disease (T. whippeli)
Visualized with PAS stain
ETEC (often with campy)
Common cause of Traveler’s diarrhea
Secondary syphilis
Maculopapular rash on palms and soles, condylomata lata
Tertiary syphilis
Chronic granulomas, aortic valve insufficiency, tabes dorsales destruction (ataxia, +Romberg, Charcot joints, stroke w/o HTN)
Congenital syphilis
Saber shins, saddle nose, Hutchinson’s teeth, deafness, mulberry molars
Tertiary syphilis
Argyll Robertson pupil